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Uh-oh. The measurement act itself can change the thing we are interested in measuring. Now we are entering the world of the Heisenberg uncertainty principle. Interesting discussion guys. I'm pleased that you keep folks in this thread grounded to reality a bit whenever it drifts off into subjective impressions. Although nothing wrong with subjective impressions (otherwise my wife would have never married me....)

If you look earlier in this thread I used a spectrum analyzer to measure the clock going into the DAC chip on a Touch. This doesn't directly measure the jitter, it measures the sidebands caused by the jitter. I could not discern any difference between decoding PCM or FLAC in the Touch. This jitter on this clock was so low the sidebands were below the noise floor of the spectrum analyzer. There might be differences in the sidebands, but the tool I have is not sufficient to measure it. There are tools that are better than this and might be better able to see it but they are VERY expensive and WAY WAY outside of what I can afford! (this was a 30K analyzer that I found used on ebay for $900, its rather rare to find 100K ones like that!)

And yes there is a reclocking flop for the clock that goes into the DAC and and a flop for the S/PDIF stream. I was measuring the DAC clock after the reclocking flop.

I think its interesting to note that I DID see significant sidebands on the DAC clock when the headphones were plugged in, which does seem to show that different electrical loads on the board CAN affect the jitter of the clock.

But this has been questioned and proved false many many times.... Things like HDCD, which has control signals buried in the dithered noise floor, WILL NOT WORK if any additional signal processing been done. The fact that they do work proves there hasn't been any additional processing done....

It was just my guess about additional processing. If there is none I'm still curious about the differences in sound of SB and Duet. As I understand jitter affects soundstage, focusing of stereo image and things like that (minor things IMHO). But why this two machines sounds totally different through DAC.

Does anybody here know how jitter actually demonstrates itself in a recording of a reasonable quality?

Which you will hear as clicking noises as samples are dropped/doubled...

Not necessarily... it depends on how much data is lost. A period of single bit errors might only result in a temporary increase in noise & distortion. Perhaps enough to be subconsciously heard as worse sounding, without obviously being dropped samples.

Some very early CD players had error lights on them, which flashed when an uncorrectable error was detected. This feature was discarded almost immediately, as there were too many customer complaints that the error light was always flashing! Ignorance is bliss! I don't believe modern CD players suffer nearly as much from this, but it would be fairly easy to test. Record the spdif stream a few times, and run them through Audio Diff Maker. You could compare the original CD with ripped and burned copies on different media, or compare different CD players this way.

i'm back from a W.E. spent with my family, not flyng Kite but Hill Walking on the snow, hope is the same for you ... :-).

Wow, lot of people now in this Thread! I think you are moving far too deep in techical matter for me, but is Ok, I'll keep on reading, may be I could learn something.

What sound strange to me is that we need to debate about the possibility that different transport sound different via the same DAC. They do, If not, why should we have so many company selling transports (and different models of them) on the market?

It's an easy test, just plug different transports to your dac and listen...

I did it (CD Players, DVD Player, SB Receiver and SB+) and for sure I could ear differences, if you don't, forget about the one I reported between FLAC and WAV.

I don't know why TRPs sound different, but what I know for sure is that - at least in my system - they do.

I also noticied that the more you take care to insulate them from power line noise and vibrations, the 'open' is the sound you have in output, cheaper equipement normaly change in greater way (SB+ less than receiver, for instance), and also cable (DIG ONE) plays his role.

I did not try with headphones, as John said, but in my experience is better to unplug the Analog OUT of the TRP when you are listening throu the SPDIF.

Some tech people says this is not just becouse the electrical charge, but also becouse the cables could operate as an 'antenna' for RFI/EMI, I'm only reporting this, I'll never sign it for sure!

Sound quality between wav and flac

marcoc1712 wrote:
> What sound strange to me is that we need to debate about the
> possibility that different transport sound different via the same DAC.
> They do, If not, why should we have so many company selling transports
> (and different models of them) on the market?

Because we are a capitalistic economy, and they sell to folks with money
to burn.

Most of the transports use the same $10 reader that is sold in the
hundreds of millions for PCs. The economies of scale essentially require
that. Engineering the speed and track following logic is non-trivial,
and you can buy it for pennies.
> I did it (CD Players, DVD Player, SB Receiver and SB+) and for sure I
> could ear differences, if you don't, forget about the one I reported
> between FLAC and WAV.

There is more to this. Assorted things we think of as "transports" are
doing more than just reading the bits and stuffing them out the S/PDIF
port. Oversampling, upsampling, filters, who knows.

> Could all of the above be refletced in Jitter?

I think jitter is an excuse for the vendors to claim that their products
are better. i.e. pure marketing hype.

Sound quality between wav and flac

DCtoDaylight wrote:
> pfarrell;502588 Wrote:
>> I think jitter is an excuse for the vendors to claim that their
>> products are better. i.e. pure marketing hype.
>
> I think the big problem is that the term jitter has been miss-used so
> much, that it has lost much credibility. I've seen -speaker cables-
> marketed as being low jitter!